Volume Flow Measurement of Autogenous and PTFE Graft Arteriovenous Fistulae for Hemodialysis of Chronic Renal Failure Patients

ABSTRACT

BACKGROUND: When it is difficult to insure adequate blood vessels, an expanded polytetrafluoroethylene (e-PTFE) graft has been accepted as an alternative although its long-term patency is not equal to that of an autogenous arteriovenous fistula (AVF) for the purpose of performing hemodialysis. There being no hemodynamic guidelines for creating an autogenous or e-PTFE AVF, we prospectively investigated the difference in blood flows between autogenous and e-PTFE AVFs after internal AVF creation in order to identify an ideal AVF. METHODS: We performed color doppler ultrasonography on 15 patients who experienced AVF creation between December 1997 and December 1998 at the Wallace Memorial Baptist Hospital in Pusan and compared the volume flow per minute, the peak systolic velocity, and the cross-sectional area between an autogenous and an e-PTFE AVF. RESULTS: Eight (8) patients experienced an autogenous vein AVF creation, and seven (7) patients experienced an AVF creation using 4x6 mm graded e-PTFE (Impra(R)). 1. Average volume flow 1611.87 +/-687.52 mL/min for autogenous AVFs and 1725.28+/-269.06 mL/min for e-PTFE AVFs (p=0.67). 2. Average peak systolic velocity 128.98+/-52.83 cm/sec for autogenous AVFs and 81.71+/-8.93 cm/sec in e-PTFE AVFs (p=0.04). 3. Average cross-sectional area 0.23+/-0.10 cm2 for autogenous AVFs and 0.34+/-0.02 cm2 for e-PTFE AVFs (p=0.02). 4. There were no postoperative complications, such as venous hypertension or distal ischemia, except for one puncture-site infection. CONCLUSIONS: There was no significant difference in volume flows between autogenous AVFs and 4x6 mm graded e-PTFE graft AVFs after internal AVF creation. In the e-PTFE graft AVFs, the cross-sectionalarea was greater and the peak systolic velocity was smaller compared with those of autogenous AVFs. These results suggest that, in e-PTFE AVF creation in order to maintain on adequate minute volume flow, it is important to minimized the cross-sectional area of the outflow vessel where the lower compliance of the e-PTFE graft increases outflow resistance. Also, we conclude that choosing the appropriate blood vessels and using a meticulous surgical technique are mandatory in establishing optimal hemodynamics for arteriovenous fistulae.